This invention concerns substituted naphthylazo-phenylazonaphthyl dyes and dye solutions.
Liquid dyes which can be pumped and measured with greater ease than powdered dyes find application wherever continuous dyeing processes are operated, as in the dyeing of paper. The best liquid dyes are true solutions which avoid difficulties with settling, a problem with thin liquid suspensions. Prior art dye solutions usually require isolation of the dye as a filter press cake before it is dissolved in a solvent or solvent mixture. The filtration rids the dye of some organic impurities as well as salts which are generated in the synthesis and tend to repress solubility of the dye itself. The composition of the instant invention provides a true dye solution containing at least 10% of dye, and can be attained without isolation of the dye from the reaction mass in which it is produced.